Stimuli‐Responsive Polymeric Systems for Biomedical Applications

Abstract

Smart polymeric‐based devices and surfaces that reversibly alter their physico‐chemical characteristics in response to their environment are the center of many studies related to the development of materials and concepts in a broad‐range of biomedical fields. Although the initial interests were more focused in systems for the delivery of therapeutic molecules, other applications have been raised in topics ranging from actuators to biomaterials for tissue engineering and regenerative medicine. The general aspects of the different types of stimuli that can be used to modulate the response are reviewed mainly for the case of hydrogels and surfaces, based on natural‐origin or biodegradable macromolecules. Thermosensitive or light responsive surfaces that can modulate cell adhesion or protein adsorption are addressed as well as less conventional smart surfaces, such as substrates onto which biomineralization may be triggered. Injectable liquids that turn to gels by the action of heating (sol‐gel thermo‐reversible hydrogels) or by changing pH or the ionic milieu (bioinspired self‐assembling systems) may find great applicability as temporary scaffolds in non invasive procedures to deliver drugs or cells to particular places in the body. Examples of systems that recognize independently or simultaneously more than one stimulus will also be presented. Besides the typical response to temperature and pH, recent developments on materials that react to biochemical stimuli, including specific enzymes, antibodies or cells, are also highlighted.

Biocompatible stimuli‐responsive nanogels for controlled antitumor drug delivery

“…Furthermore, growth cell inhibition was dependent on the concentration of DOXO into polymeric nanogels; that is, the cytotoxicity was enhanced as the concentration of DOXO released from the nanogels is increased. A similar behavior was also observed for other types of nanogels …”

Compact Saloplastic Membranes of Natural Polysaccharides for Soft Tissue Engineering

“…The results of the loss moduli ( E ″, i.e. the viscous component, see Figure S3) also correlate well with the water uptake results, since an increase of E ″ is often associated with an increase of water mass and damping properties . Herein, the damping properties were higher for M05 and lower for M0 membranes.…”

Layer‐by‐Layer Assembly of Light‐Responsive Polymeric Multilayer Systems

“…Having this in mind, during the past decades we have witnessed a huge interest in designing advanced hierarchical stimuli‐responsive functional systems that are capable to independently or simultaneously adapt and respond to one or several triggers that are inherently present in living systems, thus improving the complexity of such smart functional engineered systems. Such environmentally sensitive smart functional systems, which can be developed through many surface engineering approaches, including SAMs, chemical grafting, thin polymer network films, LbL assembly, or combinations of thereof, have received increasing attention in the past few years because they offer great advantages in exciting widespread applications, including biomedical and biotechnological, coatings and textiles, electronics, catalysis, optics, or energy applications . Thus, they aim to shed light on the development of next‐generation smart functional systems that would mimic the hierarchical organization and the behavior of smart biological systems.…”